1. Field of the Invention
This invention relates to apparatus and methods for automatically forming a vertical stack of relatively thin flat objects, all of which have generally the same horizontal shape and area. More specifically, this invention relates to apparatus and methods for automatically forming stacks of disk shaped, square shaped, rectangular shaped, or irregularly-shaped flat objects such as frozen hamburger or sausage patties.
2. Description of the Related Art:
It is known in the art to feed frozen patties into chutes, to thereby form stacks of patties. Generally, it is necessary for a worker to count the patties, and then place them into a stack within a box. This manual work is boring and repetitive, and necessarily takes place in a cold and noisy environment. The workers are thereby prone to injuries, such as carpel tunnel syndrome, and absenteeism and turnover are high.
The stacking device art includes Reissue U.S. Pat. No. 23,641 wherein paper sheets entering a stack are counted prior to the sheets hitting a fixed abutment, the sheets then dropping down onto a stack. U.S. Pat. Nos. 2,497,149, 2,672,079, 2,738,116, 3,659,728, 3,866,741, 4,902,184, and 5,116,195 are generally similar in their teaching.
In U.S. Pat. No. 3,297,174, a plurality of parallel conveyors feed a stacker apparatus. U.S. Pat. No. 3,748,797 describes an accumulator and boxer wherein a slow conveyor feeds a fast conveyor.
In U.S. Pat. No. 3,959,951, frozen patties are stacked onto a piston that moves downward as patties are stacked thereon. As the patties enter the stacking area, they strike a retaining guide member, as a top disposed piston at this location prevents upward movement of the patties. U.S. Pat. No. 4,236,855 also deals with the stacking of hamburger patties.
While devices as above described are generally useful for their limited intended purposes, the need remains for an automatically apparatus and method that accurately forms uniform vertical stacks of frozen patties as the patties exit a processing machine (for example, a freezing station).